Ivan Herman: The incubator group is finally looking at ways of mapping relational data to RDF.
This is relevant to this group in that they are interested in mapping relational data to owl structures. If all goes as planned,
it will be announced tomorrow. It will be announced on the home page as well. The charter URL is not available yet.

Ian Horrocks: This is something we would just want to keep an eye on, but not much to do now.

James Hendler: I just wanted to say that the incubator group is directly related to the discussion on fragments; the work is related to SQL queries, so we need to pay close attention to this. We should make sure that the coordination group makes sure that we don't work at cross purposes.

Ian Horrocks: So should we consider nominating someone to coordinate with this group?

Ivan Herman: I propose we should wait a week and look at the charter first. Note that the chair is from Oracle.

Pending Review Actions Discussion

Ian Horrocks: There was agreement that Boris would update the spec to address Issue 95 any objection?

Evan Wallace: I brought up in email that figure 5 does not completely reflect the change.

Jeremy Carroll: jeremy; a lot of HP work on at the moment, should ease off at easter

Publication Schedule

Ian Horrocks: Publication schedule - there is an issue from Boris regarding updating the public working drafts, which documents we might want to publish. Would we want to update the current working drafts or potentially publish other documents?

Jeremy Carroll: I think that it is good to show that we're aligned, if we are...

Sandro Hawke: The work in making another working draft is to publish a note to the public that there is another working draft, and then to publish it. If there are changes worth sharing, then sure, let's republish.

Ian Horrocks: Several people mentioned publishing the XML syntax, two things to discuss - A, are the changes sufficient to publish new versions, and B should we consider publishing additional documents.

Boris Motik: I think it would be good to show that we are aligned and something has changed. I also think we have fixed quite a few bugs, and coming up with a list of the issues we've fixed might also be good. We should consider the XML syntax and also the RDF mapping.

Ian Horrocks: Nobody else expressed anything about the other working drafts ... don't know whether that speaks for or against republishing... Perhaps if we publish both the documents and a list of the issues that have been addressed / changed / fixed that would be useful.

Ian Horrocks: Should we re-publish new version of the three already-published documents? We could take a straw pole on whether we should publish new ones. Perhaps we should do this doc by doc? Who thinks the structural syntax has changed enough?

Jeremy Carroll: I feel that we should have addressed 1 or 2 of the harder issues before republishing.

Jeremy Carroll: I'd like us to have done one or two of the harder issues before republishing -- especially given Jim's point about lack of interest in the previous draft. I wouldn't oppose publishing, but I'm not convinced it's worth the effort. [Scribe assist by Sandro Hawke]

Jeremy Carroll: We've done quite a bit of cleaning up, but something new would be more interesting -- I'm not convinced that it's work the effort.

James Hendler: My real fear is of exhausting people - if we republish for minor issues, people won't really look when we re-release for major issues. We run the risk of getting to CR and having people raise more difficult issues.

Sandro Hawke: If we publish with a list of the things we've addressed, and then ask for feedback does that make sense?

James Hendler: My sense is that people don't read the status section, and I would prefer we fix some more substantive issues before publication.

Jeremy Carroll: We can meet the heartbeat status by publishing other documents.

Sandro Hawke: q+ to ask if we should republish all when we republish any?

Ian Horrocks: So similarly, not tremendously strong support for that. So the other issue is whether or not to go forward with any of the other documents, modulo resolving the GRDDL issue with the XML syntax document. How many feel we should publish that?

Proposals to Resolve Issues

Michael Schneider: Issue 95 is only about this compatibility table, it may make sense to close this and open another regarding datatype restrictions.

Boris Motik: I actually think this is difficult to split, the table by itself is meaningless unless you say how you are applying it. When I entered this issue, I thought these two things had to be considered together. I do agree that we probably need something like named datatypes, but this issue is about fixing an error, modulo fixing the other docs. If there are other features we should discuss them separately, and limit scope.

Ian Horrocks: We should try to keep issues fairly scoped; there are a few details that you didn't get to, but hopefully they will be resolved by next week.

General Discussion

Ian Horrocks: Next issue is OWL 1.1 Full. Some of the issues related to OWL 1.1 Full are some of these difficult issues to which Jeremy was alluding when we discussed publication. We need to figure out generally how we're going to go forward on OWL 1.1 FUll, who is going to address the semantics.

Ian Horrocks: Are the semantics going to be completely new, who is going to do the work, anybody interested in doing the work?

Michael Schneider: I offer to expand the semantics to cover the new constructs ... I would need a lot of people to look over what I do if I do it. I could expand the semantics to include the new constructs as they are, but would need significant review.

Jeremy Carroll: I would offer to review / play a supportive role of the sort Michael is asking for.

Ian Horrocks: Is this the right way forward, or would we prefer to look for completely new semantics?

Jeremy Carroll: Bijan had a proposal for completely new semantics that I've lost track of, he's not on the call...

Ian Horrocks: So what do you think about this Jeremy - about extending the existing semantics?

Jeremy Carroll: To me this shouldn't be too difficult to extend the existing semantics ...we've hit an issue with the QCRs that needs to be addressed ... the property change looks quite straightforward to me. The issues are going to be where it interacts with other things, such as reification.

Ian Horrocks: Quite alot of the other issues are not saying ... there is a known problem here ... we need to discover whether there really. is an issue here, and then figure out how to address it. We seem to have a way forward here.

Michael Schneider: I think the best would be to follow what ... was done a few weeks ago, a proposal for semantics with considerations, then we can look at what the problems are.

Jeremy Carroll: We could go for a public working draft that is essentially a diff -- here are the new bits, that will be converged with the older version eventually. Clearly by working draft 2 or 3 we would actually need to do the merge.

Ian Horrocks: We should have an action on Michael to do this ... Michael, how long do you need for this ...

Michael Schneider: Since I have already done some preliminary work, we could have the start of a wiki for F2F2. A wiki version, which has language constructs and related semantics and considerations for F2F2, not a full draft, which will take a lot of writing.

ACTION: Mschneid will initiate work on the OWL 1.1 Full semantics, with a draft posted to the wiki a week prior to the next F2F meeting.

trackbot-ng: Created Action 93 - Will initiate work on the OWL 1.1 Full semantics, with a draft posted to the wiki a week prior to the next F2F meeting. [on Michael Schneider - due 2008-03-05].

Michael Schneider: It's a layered architecture, might use a rule-based semantics, taking the lead from the semantics for RDFS ... could specify this with a rule-based semantics - I think this fragment would be a good place to start

Jeremy Carroll: Is the proposal that we should define OWL prime fragment by a set of rules that would give a minimum level of entailment?

Ian Horrocks: This is something that isn't completely clear in the email on this fragments thread.

Ian Horrocks: It will help a lot to have the extended owl full semantics, which is significant progress.

Ivan Herman: The pD* and owl prime were all rule-based features in OWL 1.0, but when we look at the features to be added in OWL 1.1, there may be things worth investigating.

Zhe Wu: To Michael's comments, if he can come up with a set of rules for OWL full I will be happy to review them, then. With respect to OWL 1.1, I think the property chains can be addressed with a few rules.

Michael Schneider: I think we have in mind OWL 1.1 features ... the question was where we don't have to do too much ourselves using the pD* paper going to OWL 1.1 features, we will have to address this ourselves, especially with respect to completeness.

Jeremy Carroll: I think the pD* design has some fairly clear principles, which can guide what should be included and what can't be. We could use these design principles to extend OWL prime as a result.

Michael Schneider: Of course, OWL 1.1 features have not been asked for yet for OWL-Prime

Ian Horrocks: The main object of this discussion was to make progress on OWL Full semantics, which we have.

James Hendler: I wonder where the decision to use pd* as the formalism for OWL Prime occured

Issue Discussions

Ian Horrocks: Issue 3 - anonymous individuals ... there has been some traffic on this over the last few weeks ... are we any closer to a resolution on this?

Boris Motik: The last time there was a question as to whether it would make sense to have anonymous individuals as skolems. In the end, we don't know what the semantics of owl full are, so I don't see that we are losing anything by that.

Michael Schneider: Jim, OWL-Prime and pD* have been discussed several times together in the past. This is why I found about pD* at all

Jeremy Carroll: So, I think it depends what we mean by compatibility, from one point of view it would be backwards compatibility and another the forward view. It would allow us to deal with more graphs.

James Hendler: Mike, I've seen that, but it's one of several things under discussion as best I can tell.

Ian Horrocks: Pragmatically it wouldn't be any different, since people are doing this in practice.

Boris Motik: Pragmatically this would bring the spec in line with implementations in OWL DL. I see this as an improvement rather than a disadvantage in OWL DL. We don't know whether OWL Full model theory is satisfiable, so we are being forced into thinking about this for the sake of some phantom compatibility issue.

Uli Sattler: I just wanted to make similar points - it would indeed cover more realistically what people have implemented and expect as answers. It also reflects what people can implement - it would be extremely difficult to come up with a treatment of bnodes that would not be skolemized.

Jeff Pan: I agree to the implementation bit but not sure about the expectation bit

Ian Horrocks: It seems that several people have agreed with this point, even Jeremy is softly in agreement with this... so we might be in a position to agree that this is a way to address this issue.

Jeremy Carroll: I would need to vote against such a proposal at the moment.

Jeff Pan: I have the impression that we had discussion about the differences in the semantics, if you have unique names assumption, it is easy to show the differences, I'm not sure what people will say at the end of the day.

Boris Motik: I don't think this is the case, especially with the unique names assumtion, since OWL doesn't support this, you would have to axiomatize this yourself. Under OWL DL semantics you would have to deal with this yourself.

Ian Horrocks: I suggest that Boris writes up a kind of precise specification of what the solution would be, in the meantime Jeremy will attempt to discuss this internally to get a view of the HP position.

AOB

James Hendler: Some pieces of work get to move ahead because people in the same organization are able to make space and work on them. With respect to other things, such as fragments, we should think about how to get the work done in the context of the working group, perhaps a task force to do this.

Ian Horrocks: The way we've done this up until now was to use the wiki, admittedly we've tasked Michael to do the OWL semantics, but he was a volunteer. I think I proposed in an email that we needed to come up with a document regarding fragments, then we can discuss how to operationalize next week.

Uli Sattler: Perhaps we could do a search for people who would be willing to work on OWL prime - we don't know who would like to put in some effort here.

Ian Horrocks: This is why I sent the email, and was hoping people would step forward.